Transcriptome Analysis of ER Stress-related Genes and Validation of Reference Genes in Gene Expression RT-qPCR for Cyclocarya paliurus

Cyclocarya paliurus (Batal.) Iljinskaja (C. paliurus) is a unique tree species in China appreciated for its pharmacodynamic components. However, abiotic stresses, such as drought, salt, cold, or heat, which cause the accretion of misfolded or unfolded proteins in the endoplasmic reticulum (ER), induce a reduction in the yield of C. paliurus. Unfolded protein response (UPR) induced by ER stress plays a critical role in the development and adaptation of plants to adverse environmental stresses. Hence, this study aimed to investigate the genetic mechanisms of ER stress in C. paliurus by performing transcriptome analysis to compare the ER stress-related gene expression during tunicamycin (TM) treatment for different time durations (0, 6, and 14 h). A total of 196,207 unigenes were detected, with 1867 downregulated and 3040 upregulated in the treatment groups (TM_6 h and TM_14 h) compared with the control group (TM_O h). In this study, nine upregulated genes were randomly selected to validate transcriptome data by real-time quantitative polymerase chain reaction (RT-qPCR). In addition, the proper number and type of reference genes to be used in the normalization of RT-qPCR were found in studies of C. paliurus; ACT2 and TUB were the most appropriate reference options in the TM treatments. The results from this study might provide insights for the genetic basis of ER stress in C. paliurus. (C) 2019 Friends Science Publishers